Not sure if someone can provide you ready to use document, because these are personalized and environment specific things. You can consider the below approach if you want to write your own document.

If you are looking to onboard Database servers oracle/Unix then it is quite simple, As per my understanding, the underlying server will either be Unix or Windows. So you should use the same approach as you would do for onboarding any windows server or Unix servers. Something which you should take is that how you are going to manage those servers in PAM, Is it automated or manual.

If you want to do it automated then you can user AD Security Groups to achieve that in case of Windows.For Unix either you can use manual device creation process or AD Security Group if Unix devices are joined in your domain(i have not used this personally ).

In case If you are looking how to manage Account of Oracle and SQL database then you may refer below links.